Oscillating wave cells in which two or more immiscible fluids of different colors are contained in an oscillating vessel to display fluid wave motion are well known. One such wave cell is disclosed in U.S. Pat. No. 3,613,264, to Vitka, et. al.
As disclosed in Vitka, the vessel is rectangular in shape and closed to the atmosphere. In addition to the two immiscible fluids, the vessel contains a small quantity of air to accommodate thermal expansion and contraction of the vessel and the liquids. In order to provide bubble-free display of the fluid motion, the wave cell includes an air trap located on one end of the vessel. An opaque end cover can be used to conceal the air trap. However, the end cap prevents full viewing of the fluid motion.
The present invention is provided to solve this and other problems.